KR20170096996A - Melt spinnable copolymers from polyacrylonitrile, method for producing fibers or fiber precursors by means of melt spinning, and fibers produced accordingly - Google Patents

Abstract

The present invention relates to a melt-spinnable copolymer of polyacrylonitrile (PAN) which can be prepared by copolymerization of acrylonitrile with alkoxyalkylacrylate. Alkyl acrylates and vinyl esters may be considered as additional comonomers. Likewise, the invention relates to a process for the production of fiber or fiber precursors, in particular carbon fiber precursors, by melt spinning, in which the abovementioned copolymers are used. The invention also relates to fibers, in particular carbon fibers, produced in this way.

Description

MELT SPINNABLE COPOLYMERS FROM POLYACRYLONITRILE, METHOD FOR PRODUCING FIBERS OR FIBER PRECURSORS BY MEANS OF MELT SPINNING, AND AND METHODS FOR PRODUCING FIBERS OR FIBER PRECURSORS BY MELTED RADIATION FIBERS PRODUCED ACCORDINGLY}

The present invention relates to a melt-spinnable copolymer of polyacrylonitrile (PAN) which can be prepared by copolymerization of acrylonitrile with alkoxyalkylacrylate. Alkyl acrylates and vinyl esters may be considered as additional comonomers. Likewise, the invention relates to a process for the production of fiber or fiber precursors, in particular carbon fiber precursors, by melt spinning, in which the abovementioned copolymers are used. The invention also relates to fibers, in particular carbon fibers, produced in this way.

According to the state of the art, carbon fibers, which are becoming more important in the field of textile technology, are produced by thermal conversion of separately prepared precursor fibers. The materials for the precursor fibers are, above all, PAN (co) polymers (acrylic precursors) and pitch. Until now, acrylic precursor fibers have been produced exclusively and commercially through a wet-spinning method or a dry-spinning method. For this purpose, the polymer solution with a concentration of < 20% is spun in a coagulation bath or a hot steam atmosphere to discharge the solvent out of the fiber. In this way, a very high quality precursor is produced, but the cost of this method is relatively high. On the one hand, the required solvent and its handling, on the other hand, are costly due to the relatively low throughput in the solution spinning method.

Due to strong intermolecular interactions and intramolecular interactions of nitrile groups, the melting point of PAN is as high as 320 ° C, which is higher than the decomposition temperature of the polymer. This makes melt spinning of pure PAN impossible and means that the polymer acts as a duroplast, not a thermoplast. At the same time, the possibility of producing precursor fibers by melt spinning results in a significant cost savings in precursor production, since there is substantially no throughput during melt spinning and no solvents that lead to purchase and recycling / disposal costs something to do.

We have been working for decades to make PAN spin-melt spinning. This should, in principle, distinguish between external softening (mixing of additives and polymers) and internal softening (copolymerization). In both cases, the interaction of the nitrile groups is thereby disturbed and melting occurs below the decomposition temperature of the polymer.

An essential prerequisite for further processing to form carbon fibers is the stabilization of the fibers and the subsequent possibility of oxidative stabilization. This process is performed at a temperature of 200 ° C or higher, and then forms a cyclic structure that allows carbonization. This, of course, can only succeed when the fiber is not melting at the stabilization temperature - this leaves a further problem to be solved since the stabilization temperature is generally higher than the processing temperature during melt spinning.

Internal softening is achieved by copolymerization with a suitable comonomer. Already in 1970, GB 1270504 describes the preparation of thermoplastic acrylonitrile copolymers for fiber production by melt spinning at 200-240 ° C. Textile fibers (textile fibers) are applications. Thus, from 8 to 50% by weight of aliphatic alkene / alicyclic alkenes and / or acrylates are used as comonomers and are selected from the group consisting of methylacrylate, ethylacrylate, butyl acrylate butylacrylate, isobutene, vinyl acetate and propene are listed as application examples. In addition, the copolymer comprises 0.2 to 10% by weight of sulfonic acid group-containing monomers. However, because of the cyclisation reaction of the nitrile groups, which are not stable in melt viscosity and are catalyzed by acid groups, these acid group-containing copolymers are inevitably melted The viscosity is increased and it is not suitable for the continuous melt spinning method.

US 3499073 describes a technique in which a thermoplastic PAN copolymer is prepared with the aid of an organometallic catalyst. Polymers which are homopolymers of PAN can be processed to form monofilaments at a temperature of from 250 캜 to 295 캜.

GB1294044 contains 60 to 70% of acrylonitrile, 25 to 30% of methacrylonitrile and 5 to 10% of acrylate or methacrylate and has softening points of 125 to 175 占 폚, Acrylonitrile < / RTI > copolymers. At the stated softening point, the polymer is not present as a melt but is present as a flexible film.

US 4,107,252 describes copolymers of acrylonitrile having 12 to 18% by weight of styrene and 13 to 18% by weight of isobutene, the melting temperature being 175 캜 to 260 캜. However, the comonomer content is too high to produce carbon fibers from such copolymers. In general, it is assumed that the PAN copolymer suitable for carbon fibers should include the average chain length of the continuous acrylonitrile unit 9 or higher. In practice, only about 10 mole% of comonomer content can be tolerated.

EP0030666 describes a thermoplastic acrylonitrile copolymer for hoses and films having an acrylonitrile content of up to 96%, which is prepared by grafting acrylonitrile to an elastomer phase. Such polymers have branched structures due to grafting and are not suitable for fiber production.

GB 2356830 describes the thermoplastic formation of acrylonitrile polymers having a 96-100% acrylonitrile content by a special pressure and temperature method, but excludes the possibility of use for melt spinning due to the required extruder high pressure.

US5618901 describes a process for the preparation of thermoplastic acrylonitrile copolymers consisting of 50-95% of acrylonitrile and 5-50% of comonomers, wherein all possible comonomer classes (acrylate, methacrylate, acrylamide Containing monomer, an acid group-containing monomer, an amino group-containing monomer, an olefin-based monomer, an acrylate-based monomer, an acrylate-based monomer, an acrylamide derivative, an acrylamide derivative, a methacrylamide derivative, vinyl ester, vinyl ether, vinylamide, vinyl ketone, styrene, And combinations thereof). Embodiments refer to methylstyrene, styrene, vinyl acetate, methyl acrylate and methyl methacrylate having a proportion of at least 15% by weight of the copolymer (corresponding to about 10 mol% in the case of methyl acrylate). The copolymer can be extruded at 200 < 0 > C.

US 6114034 describes precisely the preparation of fibers from these copolymers, in which methyl acrylate and vinyl acetate are used as comonomers, in practice in proportions of 15 to 25% by weight. The fiber can be made with a diameter of 3 to 8 dtex and a strength of 29 cN / tex (15% methyl acrylate) or 55 cN / tex (25% methyl acrylate) (55,000 g / mol) to 240 DEG C (90,000 g / mol). However, some studies show that such copolymers do not have a stable melt viscosity. The copolymers with a molar mass of 10 mol% MA and 126 000 g / mol showed an increase in the complex viscosity by 35% after 20 minutes at 200 DEG C, 20 mol% methyl acrylate and 68,000 g / mol was also increased by 10% in the copolymer having a molar mass. When the complex viscosity according to the temperature is observed, it is found that the copolymer having 10 mol% of methyl acrylate has a decrease in the complex viscosity according to the temperature up to 220 DEG C and decomposition processes at higher temperatures. And the start of stabilization processes. This instability is incompatible with the technical melt spinning process. It causes cracks at the hot points of spinning extruders, spinning pumps and spinning nozzles and causes defects in the spun fibers. The melt-spinnable PAN precursor should have a maximum of 11 mole percent comonomer and must be processable at a maximum temperature of 220 ° C while at the same time be able to withstand a temperature peak due to the mechanical stresses of the spinning extruder and spinning pump To maintain a stable melt viscosity of at least 240 ° C.

In WO 00/50675, the use of such copolymers for the production of carbon fiber precursors has been patented. However, in terms of content, the patent does not surpass US6114034. Methyl acrylate, ethyl acrylate, methyl methacrylate and vinyl acetate are indicated as preferred comonomers.

It is an object of the present invention to provide a precursor based on polyacrylonitrile which exhibits improved compatibility with the melt spinning process.

This object is achieved by a copolymer having the features of claim 1 and to a process for the production of fibers by melt spinning having the features of claim 11 and to fibers having the features of claim 15. Other subclauses disclose advantageous improvements.

According to the present invention, a melt-spinnable copolymer of polyacrylonitrile (PAN) is provided, which can be prepared by copolymerization of 95 to 80 mole% of acrylonitrile with at least one comonomer, The at least one comonomer is selected from:

a) 5 to 20 mol% of at least one alkoxyalkylacrylate of formula (I)

Wherein R = C _n H _{2n +1} and n = 1-8 and m = 1-8, especially n = 1-4 and m = 1-4,

b) from 0 to 10 mol% of at least one alkyl acrylate of formula (II)

Wherein R = C _n H _{2n + 1} and n = 1-18,

c) from 0 to 10 mol% of at least one vinyl ester of formula (III)

Where R = C _n H _{2n + 1} and n = 1-18.

Thus, the weight-average molar mass (Mw) of the copolymer is in the range of 10,000 to 150,000 g / mol.

The copolymer is preferably spinnable in a temperature range of 160 to 240 캜, particularly 180 to 220 캜.

The copolymers according to the invention preferably have a melt viscosity which is constant or decreasing with increasing temperature up to 240 ° C, in particular up to 260 ° C. This proves that the copolymers according to the invention have a particularly high stability of the melt viscosity.

The copolymerization is preferably carried out by precipitation polymerisation, emulsion polymerization and / or polymerization in a solvent. Thus, the solvent is preferably selected from the group consisting of dimethylsulphoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylene carbonate, Propylene carbonate, aqueous sodium rhodanide solution, and mixtures thereof.

The proportion of the at least one alkoxyalkyl acrylate is preferably 8 to 12 mol%.

A further preferred embodiment provides that a mixture of at least one alkoxyalkyl acrylate and at least one comonomer of alkyl acrylate is present. Accordingly, the ratio of the at least one alkyl acrylate may preferably be in the range of 1 to 5 mol%.

A further preferred embodiment provides that a mixture of at least one alkoxyalkyl acrylate and at least one vinyl ester is present. Whereby the proportion of the at least one vinyl ester is preferably in the range of 1 to 5 mol%. More preferably, the copolymer has a weight-average molar mass (Mw) in the range of 15,000 to 80,000 g / mol.

Likewise, alkoxyalkyl acrylates may be used as comonomers with alkyl acrylates and vinyl esters.

According to the present invention, there is also provided a process for producing a fiber or fiber precursor by melt spinning,

i. The copolymerization of 95 to 80 mol% of acrylonitrile with at least one comonomer selected in the presence of at least one initiator takes place; and

a) 5 to 20 mol% of at least one alkoxyalkyl acrylate of formula (I);

Wherein R = C _n H _{2n + 1} and n = 1-8 and m = 1-8, especially n = 1-4 and m = 1-4,

b) from 0 to 10 mol% of at least one alkyl acrylate of formula II;

Wherein R = C _n H _{2n + 1} and n = 1-18,

c) 0 to 10 mol% of at least one vinyl ester of formula (III);

Wherein R = C _n H _{2n + 1} and n = 1-18,

ii. Spinning the copolymer with an extruder having at least one nozzle suitable for spinning to form a monofilament or multifilament at the extruder outlet; .

Thus, at least one softening agent may be added before extrusion or extrusion of ii), and in particular the softening agent may be selected from the group consisting of water, nitroalkanes, alkylalcohols, ionic liquids, glycols, , Dimethylsulphoxide, dimethylformamide, dimethylacetamide, dimethylformamide, ethylene carbonate, propylene carbonate, aqueous sodium rhodanide solution, and mixtures thereof. Lt; / RTI > When a softener is added, a pressure chamber can be connected behind the nozzle to prevent evaporation, such as an explosion of boiling softeners below the processing temperature.

When the fibers are associated with carbon fibers, the following two successive steps are preferably implemented:

i. Stabilizing the filament by temperature treatment at a temperature of 200 to 350 DEG C, and

ii. Carbonization of the filament at a temperature of 800 to 1,200 ° C.

The step of stabilizing the filament is preferably carried out at a temperature of 180 to 320 캜, preferably 180 to 300 캜, particularly preferably 180 to 250 캜.

Also, during the copolymerization of step (i), the initiator of the radical polymerization may be selected from azo compounds, peroxides, hydroperoxides, alkylperoxides, peroxydicarbonates, peroxodicarbonates, peroxyesters, dialkylperoxides, persulphates, perphosphates, redox initiators, and mixtures thereof.

According to the present invention, fibers, especially carbon fibers, which are producible according to the method described above are provided.

Figures 1 to 11 show the temperature dependence of the viscosity for the embodiments described below with reference to the figures.
1 shows a rheological measurement in an oscillation mode (temperature sweep) of Comparative Example 1. Fig.
2 shows a rheological measurement in an oscillation mode (temperature sweep) of Comparative Example 2. Fig.
Figure 3 shows a rheological measurement in an oscillation mode (temperature sweep) of an embodiment according to the present invention.
Figure 4 shows rheological measurements in an oscillation mode (temperature sweep) of another embodiment according to the present invention.
Figure 5 shows a rheological measurement in an oscillation mode (temperature sweep) of another embodiment according to the present invention.
Figure 6 shows a rheological measurement in an oscillation mode (temperature sweep) of another embodiment according to the present invention.
Figure 7 shows a rheological measurement in an oscillation mode (temperature sweep) of another embodiment according to the present invention.
Figure 8 shows a rheological measurement in an oscillation mode (temperature sweep) of another embodiment according to the present invention.
Figure 9 shows a rheological measurement in an oscillation mode (temperature sweep) of another embodiment according to the present invention.
Figure 10 shows a rheological measurement in an oscillation mode (temperature sweep) of another embodiment according to the present invention.
Figure 11 shows a rheological measurement in an oscillation mode (temperature sweep) of another embodiment according to the present invention.

The subject matter according to the invention will be described in more detail with reference to the following examples and drawings without limiting the subject matter to the particular embodiments described herein. Figures 1 to 11 show the temperature dependence of the viscosity for the embodiments described below with reference to the figures.

Example

In the following examples, the following devices were used:

Mini-Haake: relates to the mini-2-screw extruder "HAAKE Minilab" of Thermo Electron Corporation of Germany. A 1-hole-nozzle having a hole diameter of 500 mu m was provided in the melt outlet opening. Were measured by hand. The emerging monofilament exits the winding head (up to 400 m / min) and is wound on the bobbin.

Multi-Filament-Spinning (Spinning tester): The apparatus includes a twin-screw extruder (L / D = 30) with four temperature zones. It was gravimetrically measured under a nitrogen atmosphere and the temperature was adjusted to a maximum temperature of 40 ° C. At the extruder end, a spinning packet having a melt filter (100 mu m) and a nozzle plate (42-hole nozzle, 400 mu m hole diameter, L / D = 4) A galette duo capable of drawing at a maximum speed of 100 m / min was used as a draw-off element. The final winding of the filament yarn was produced by a cross-wound cone winder.

Comparative Example  One

Precipitation polymerization to form a copolymer having 10 mole% of methyl acrylate and radiation in Mini-Haake

To a jacketed reactor equipped with reflux cooling and anchor agitator were charged 340 g of water, 0.39 g of ascorbic acid and 0.2 g of mercaptoethanol under nitrogen purging, Respectively. 6.1 g of methyl acrylate and 33.9 g of acrylonitrile was added. This is heated to an internal reactor temperature of 30 ° C and 200 μl of a 1% solution of iron (II) sulphate heptahydrate in 1% is added followed by 0.45 and ammonium persulphate in 10 g of water, Add the solution. After 1.5 hours, the reaction is terminated and the reactor contents are filtered, washed with water and ethanol and dried in vacuo.

The resulting polymer has a relative viscosity of 2.0. About 9.7 mol% of methyl acrylate and 90.3 mol% of acrylonitrile.

Figure 1 shows rheological measurements in an oscillation mode (temperature sweep).

The complex viscosity increases at temperatures above 220 캜.

In Mini-Haake, the polymer was spun to form a monofilament with a maximum draw-off speed of 40 m / min at 230 ° C. A faster draw-off speed could not be achieved. A stable spinning process for a considerably long time was impossible.

Comparative Example  2

Solution polymerization to form a copolymer having 10 mole% of methyl acrylate and radiation in Mini-Haake

72 g of N-methylpyrrolidone was added to a 250 mL round flask equipped with a reflux cooler and a nitrogen inflow under magnetic agitation. 7.4 g of methyl acrylate and 40.6 g of acrylonitrile was added and heated to 60 DEG C in an oil bath. After reaching the temperature, a solution of 180 mg V-65 (2,2'-azobis (2,4-dimethylvaleronitrile), 2-dimethylvaleronitrile, Co. Wako The reaction mixture was precipitated in 500 ml of ethanol and the polymer was filtered, washed with ethanol and dried under vacuum.

The relative viscosity of the resulting polymer is 1.5. The molar mass (Mw) was measured at 29,000 g / mol and the PDI was 1.5. 9.3 mol% of methyl acrylate, and 90.7 mol% of acrylonitrile. ≪ tb > < TABLE >

Figure 2 shows rheological measurements in an oscillation mode (temperature sweep).

The complex viscosity increases at temperatures above 230 [deg.] C.

The polymer was radiated to form monofilaments at Mini-Haake at 220 [deg.] C with a maximum draw-off speed of 200 m / min. A stable spinning process for a considerably long time was impossible.

Example  One

Precipitation polymerization to form a copolymer having 10% methoxyethylacrylate (m = 2; n = 1) and spinning in Mini-Haake

To a jacketed reactor equipped with reflux cooling and anchor agitator, 340 g of water, 0.39 g of ascorbic acid and 1.0 g of mercaptoethanol were added under nitrogen purging . A mixture of 8.6 g of methoxyethylacrylate and 31.4 g of acrylonitrile was added. This was heated to an internal reactor temperature of 30 ° C. and 200 μl of a 1% iron (II) sulphate heptahydrate solution was added, and then 0.45 g of ammonium persulphate in 10 g of water, Add the solution. After 1.5 hours, the reaction is terminated and the reactor contents are filtered, washed with water and ethanol and dried in vacuo.

The resulting polymer has a relative viscosity of 1.4. The molar mass (Mw) was measured at 22,000 g / mol and the PDI was 2.3. 1 < / RTI > 0.2 mol% methoxyethyl acrylate and 89.8 mol% acrylonitrile.

Figure 3 shows rheological measurements in an oscillation mode (temperature sweep).

The complex viscosity does not increase again to a temperature of at least 255 캜.

The polymer was spun in a Mini-Haake to form a monofilament with a maximum draw-off speed of 200 m / min at 180 ° C. The fiber had a titre of 2.8tex, a strength of 16.4cN / tex and a breaking elongation of 16.4%.

Example  2

Solution polymerisation to form a copolymer with 10% methoxyethylacrylate and radiation in Mini-Haake

To a 250 mL round flask equipped with a reflux cooler and a nitrogen inflow, 80 g of dimethylsulphoxide was added under magnetic stirring. A mixture of 4.3 g of methoxyethyl acrylate, 15.7 g of acrylonitrile and 500 mg of mercaptoethanol was added and heated to 60 DEG C in an oil bath. After reaching the temperature, 250 mg of V-65 (2,2'-azobis (2,4-dimethylvaleronitrile), 2,4-dimethylvaleronitrile, Co. Wako The reaction mixture was precipitated in 500 ml of ethanol and the polymer was filtered, washed with ethanol and dried under vacuum.

The resulting polymer has a relative viscosity of 1.4. About 9.7 mol% of methoxyethyl acrylate and 90.3 mol% of acrylonitrile. ≪ tb > < TABLE >

The polymer was spun in a Mini-Haake to form monofilaments at 180 DEG C with a maximum draw rate of 400 m / min. The fiber had a titre of 1.0 tex, a strength of 11.5 cN / tex and a breaking elongation of 19.0%.

Example  3

Solution polymerization to form copolymerization with 10% methoxyethyl acrylate and radiation in Mini-Haake

36 g of N-methyl-2-pyrrolidone (NMP) were added under magnetic stirring to a 100 ml round-bottomed flask equipped with a reflux cooler and a nitrogen inflow . 5.15 g of methoxyethyl acrylate, 18.85 g of acrylonitrile was added and heated to 60 DEG C in an oil bath. After reaching the temperature, 98 mg of V-65 (2,2'-azobis (2,4-dimethylvaleronitrile), 2, 2'-azobis The reaction mixture was precipitated in 500 ml of water, the polymer was filtered, washed with ethanol and dried in vacuo.

The resulting polymer has a relative viscosity of 1.6. The molar mass Mw was measured at 44,000 g / mol and the PDI was 1.4. About 9.6 mol% methoxyethyl acrylate and 90.4 mol% acrylonitrile.

Figure 4 shows rheological measurements in an oscillation mode (temperature sweep).

The complex viscosity does not increase again to a temperature of at least 250 ° C.

The polymer was spun in a Mini-Haake to form monofilaments at a maximum withdrawal rate of 118 m / min at 180 ° C. The fiber had a titre of 4.3 tex, a strength of 18.3 cN / tex and a breaking elongation of 16.5%.

Example  4

Solution polymerization to form a copolymer having 10% butoxyethylacrylate (m = 2, n = 4) and spinning in Mini-Haake

36 g of N-methyl-2-pyrrolidone (NMP) were added under magnetic stirring to a 100 ml round-bottomed flask equipped with a reflux cooler and a nitrogen inflow . A mixture of 6.4 g of butoxyethylacrylate and 17.6 g of acrylonitrile was added and heated to 60 DEG C in an oil bath. After reaching the temperature, 92 mg of V-65 (2,2'-azobis (2,4-dimethylvaleronitrile), 2, 2'-azobis The reaction mixture was precipitated into 500 ml of water, the polymer was filtered, washed with ethanol and dried under vacuum.

The resulting polymer has a relative viscosity of 1.6. And approximately corresponds to the feed values of a composition having 9.7 mol% butoxyethylacrylate and 90.3 mol% acrylonitrile.

Figure 5 shows rheological measurements in an oscillation mode (temperature sweep).

The complex viscosity does not increase again to a temperature of at least 250 ° C.

The polymer was spun in a Mini-Haake at 200 ° C to form monofilaments with a maximum draw rate of 98 m / min. The fiber had a titre of 8 tex, a strength of 9.5 cN / tex and a breaking elongation of 14.2%.

Example  5

Solution polymerization to form copolymerization with 7.5% methoxyethyl acrylate and spinning in Mini-Haake

To a 1.8 L stainless steel reactor were added 222.0 g of N-methyl-2-pyrrolidone (NMP), 123.4 g of acrylonitrile and 24.6 g of 2-methoxyethyl acrylate methoxyethylacrylate) was introduced and inactivated with nitrogen for 15 minutes by an inlet pipe. The closed reactor was then heated to 55 DEG C and 615 mg of V-40 (1,1'-azobis (cyclohexanecarbonitrile)), Co. Wako (cyclohexanecarbonitrile) ) Solution was injected into the syringe through the inlet. The reaction mixture is stirred at 90 < 0 > C for 6 hours.

After the reaction, the mixture is put into 2 L of NMP and precipitated in 5 times water. After filtering the polymer, it is washed with water and ethanol and dried under vacuum at 60 < 0 > C.

The resulting polymer has a relative viscosity of 1.4. The molar mass (Mw) was measured at 38,000 g / mol and the PDI was 1.2. 7.1 mol% of methyl acrylate, and 92.9 mol% of acrylonitrile.

Figure 6 shows rheological measurements in an oscillation mode (temperature sweep).

The complex viscosity does not increase again to a temperature of at least 250 ° C.

The polymer was spun in a Mini-Haake at 200 ° C to form monofilaments with a maximum draw rate of 98 m / min. The fiber had a titre of 7.3 tex, a strength of 7.7 cN / tex and a breaking elongation of 16.8%.

Example  6

Solution polymerization in which the copolymer with 10% methoxyethylacrylate is formed and spinning in a spinning tester

To a 7.5 L stainless steel reactor were added 3,000 g of N-methyl-2-pyrrolidone (NMP), 1,630 g of acrylonitrile and 449 g of 2-methoxyethylacrylate ) Is introduced and inactivated with nitrogen by an inlet pipe for 15 minutes. After the sealed reactor was heated to 55 占 폚, a solution of 8.8 g of V-40 (1,1'-azobis (cyclohexanecarbonitrile)), Co. Wako ) Solution was injected into the syringe through the inlet. The reaction mixture is stirred at 90 < 0 > C for 6 hours.

After the reaction, the mixture is precipitated in 5 times water. After filtering the polymer, it is washed with water and ethanol and dried under vacuum at 60 < 0 > C.

The resulting polymer has a relative viscosity of 1.3. Approximately 9.7 mol% of methyl acrylate and 90.3 mol% of acrylonitrile.

Figure 7 shows rheological measurements in an oscillation mode (temperature sweep).

The complex viscosity does not increase again to a temperature of at least 250 ° C.

The polymer was spun in a radial tester under the following conditions: Temperature zone in the extruder 110 占 폚 / 160 占 180 占 180 占 폚; Spinning nozzle temperature 180 ° C; Maximum draw speed 100m / min. Each fiber had a titre of 0.82tex, a strength of 16.3cN / tex, and a breaking elongation of 17.6%.

At a drawing speed of 40 m / min, each fiber titer of 2.1 tex was obtained, the strength was 10.1 cN / tex, and the breaking elongation was 53.6%. The fibers were again stretched in hot water at 80 占 폚. Each fiber had a titre of 0.80 tex, a strength of 22.4 cN / tex, and a breaking elongation of 19.0%.

Example  7

Solution polymerization to form a copolymer having 10% methoxyethylacrylate and radiation in a spinning tester

To a 1.8 L steel reactor were added 499.5 g of N-methyl-2-pyrrolidone (NMP), 166.5 g of DMSO, 348.8 g of acrylonitrile and 95.1 g of 2-methoxyethyl Acrylate was introduced and inactivated with nitrogen for 15 minutes by an inlet pipe. The closed reactor was heated to 55 DEG C and 1.79 g of V-40 (1,1'-azobis (cyclohexanecarbonitrile)), Co. Wako (cyclohexanecarbonitrile) ) Solution was injected through the syringe at the inlet. The reaction mixture is stirred at 90 < 0 > C for 6 hours.

After the reaction, the mixture is put into 2 L of NMP and precipitated in 5 times water. After filtering the polymer, it is washed with water and ethanol and dried under vacuum at 60 < 0 > C.

The resulting polymer has a relative viscosity of 1.6. Corresponds to feed values of a composition having 10.1 mol% of methyl acrylate and 89.9 mol% of acrylonitrile.

The polymer was spun in a radial tester under the following conditions: Temperature zone in the extruder 110 占 폚 / 160 占 185 占 폚 200 占 폚; Spinning nozzle temperature 200 캜; Maximum draw speed of 30m / min. Each fiber had a titre of 0.92 tex, a strength of 20.3 cN / tex and a breaking elongation of 20.9%.

Example  8

Solution polymerization to form a copolymer with 9% methoxyethylacrylate and 1% dodecylacrylate, and radiation in Mini-Haake

To a 1 liter steel reactor were added 222.0 g of N-methyl-2-pyrrolidone (NMP), 114.2 g of acrylonitrile, 28.0 g of 2-methoxyethyl acrylate and 5.75 g of Dodecylacrylate is introduced and inactivated with nitrogen for 15 minutes by an inlet pipe. The closed reactor was then heated to 55 DEG C and 583 mg of V-40 (1,1'-azobis (cyclohexane carbonitrile)), Co. Wako) solution was injected through the syringe at the inlet. The reaction mixture is stirred at 90 < 0 > C for 6 hours.

After the reaction, the mixture is put into 1 L of NMP and precipitated in 5 times water. After filtering the polymer, it is washed with water and ethanol and dried under vacuum at 60 < 0 > C.

The resulting polymer has a relative viscosity of 1.4. This corresponds approximately to the feed values of a composition having 8.8 mol% methoxyethyl acrylate, 1 mol% dodecyl acrylate and 90.2 mol% acrylonitrile.

8 shows rheological measurements in an oscillation mode (temperature sweep).

The complex viscosity does not increase at a temperature of 230 DEG C or higher.

The polymer was spun in a Mini-Haake at 200 < 0 > C to form monofilaments at a maximum draw rate of 400 m / min. The fiber had a titre of 3.8 tex, a strength of 7.5 cN / tex and a breaking elongation of 107.5%.

Example  9

Solution polymerization to form a copolymer having 8% methoxyethyl acrylate and 2% dodecyl acrylate, and spinning in Mini-Haake

To a 1 liter steel reactor were added 222.0 g of N-methyl-2-pyrrolidone (NMP), 112.2 g of acrylonitrile, 24.5 g of 2-methoxyethyl acrylate and 11.3 g of dodecyl acrylate, And inactivated with nitrogen by an inlet pipe for 15 minutes. The closed reactor was then heated to 55 DEG C and 575 mg of V-40 (1,1'-azobis (cyclohexanecarbonitrile)), Co. Wako (cyclohexanecarbonitrile) ) Solution was injected through the syringe into the inlet. The reaction mixture was stirred at 90 < 0 > C for 6 hours.

After the reaction, the mixture is put into 1 L of NMP and precipitated in 5 times water. After filtering the polymer, it is washed with water and ethanol and dried under vacuum at 60 < 0 > C.

The resulting polymer has a relative viscosity of 1.4. Approximately corresponds to the feed values of a composition having 7.9 mol% of methoxyethyl acrylate, 1.9 mol% of dodecyl acrylate and 90.2 mol% of acrylonitrile.

Figure 9 shows rheological measurements in an oscillation mode (temperature sweep).

The complex viscosity does not increase at a temperature of 230 DEG C or higher.

Polymer was radiated in Mini-Haake at 200 ° C to form monofilaments with a maximum draw rate of 400 m / min. The fiber had a titre of 2.5 tex, a strength of 9.1 cN / tex and a breaking elongation of 76.2%.

Example  10

Solution polymerization to form a copolymer having 7% methoxyethyl acrylate and 3% dodecyl acrylate, and spinning in Mini-Haake

To a 1 liter steel reactor were added 222.0 g of N-methyl-2-pyrrolidone (NMP), 110.3 g of acrylonitrile, 21.0 g of 2-methoxyethyl acrylate and 16.6 g of dodecyl acrylate, Min by the inlet pipe. The closed reactor was then heated to 55 DEG C and 565 mg of V-40 (1,1'-azobis (cyclohexanecarbonitrile)), Co. Wako (cyclohexanecarbonitrile) ) Solution was injected into the syringe through the inlet. The reaction mixture is stirred at 90 < 0 > C for 6 hours.

After the reaction, the mixture is put into 1 L of NMP and precipitated in 5 times water. After filtering the polymer, it is washed with water and ethanol and dried under vacuum at 60 < 0 > C.

The resulting polymer has a relative viscosity of 1.4. Approximately corresponds to the feed values of a composition having 6.8 mol% of methoxyethyl acrylate and 3.0 mol% of dodecyl acrylate and 90.2 mol% of acrylonitrile.

Figure 10 shows rheological measurements in an oscillation mode (temperature sweep).

The complex viscosity does not increase at a temperature of 230 DEG C or higher.

Polymer was radiated in Mini-Haake at 200 ° C to form monofilaments with a maximum draw rate of 400 m / min. The fiber had a titre of 2.3 tex, a strength of 10.7 cN / tex and a breaking elongation of 29.7%.

Example  11

Solution polymerization to form a copolymer having 5% methoxyethyl acrylate and 5% methyl acrylate, and spinning in Mini-Haake

In a 100 ml round flask equipped with a reflux cooler and a nitrogen inflow, 36 g of N-methylpyrrolidone was added under magnetic stirring. A mixture of 1.8 g of methyl acrylate, 2.7 g of methoxyethyl acrylate and 19.6 g of acrylonitrile was added and heated to 60 DEG C in an oil bath. After reaching the temperature, 90 mg of V-65 (2,2'-azobis (2,4-dimethylvaleronitrile)) (2, 2-azobis Wako)) solution was added. The reaction time is 6 hours. The reaction mixture was precipitated in water, the polymer was filtered, washed with ethanol and dried under vacuum.

The relative viscosity of the resulting polymer is 1.5. The molar mass (Mw) was measured at 47,000 g / mol and the PDI was 1.1. Approximately corresponds to the feed values of a composition having 5.3 mole percent methoxyethyl acrylate, 4.5 mole percent methyl acrylate, and 90.2 mole percent acrylonitrile.

11 shows the rheological measurement in the oscillation mode (temperature sweep).

The complex viscosity does not increase at a temperature of 230 DEG C or higher.

The polymer was spun in a Mini-Haake to form a monofilament with a maximum draw rate of 98 m / min at < RTI ID = 0.0 > 190 C. < / RTI > The fiber had a titre of 2.4 tex, a strength of 15.0 cN / tex and a breaking elongation of 13.8%.

Claims (16)

A spinnable copolymer of polyacrylonitrile (PAN), which can be prepared by copolymerizing 95 to 80 mole% of acrylonitrile and at least one comonomer,
Wherein said at least one comonomer is selected from:
a) 5 to 20 mol% of at least one alkoxyalkyl acrylate of formula (I)

Wherein R = C _n H _{2n +1} , n = 1-8 and m = 1-8, especially n = 1-4 and m = 1-4,
b) from 0 to 10 mol% of at least one alkyl acrylate of formula II, and

Wherein R = C _n H _{2n + 1} and n = 1-18,
c) from 0 to 10 mol% of at least one vinyl ester of formula (III)

Wherein R = C _n H _{2n +1} and n = 1-18,
Wherein the weight-average molar mass (Mw) of the copolymer is in the range of 10,000 to 150,000 g / mol. The method according to claim 1,
Wherein the copolymer is spinnable in a temperature range of from 160 to 240 캜, especially from 180 to 220 캜. 3. The method according to claim 1 or 2,
Wherein the copolymer has a melt viscosity that is constant or decreasing with increasing temperature up to 240 占 폚, especially up to 260 占 폚. 4. The method according to any one of claims 1 to 3,
Wherein the copolymerization is carried out by precipitation polymerization in an aqueous medium, emulsion polymerization in an aqueous medium and / or polymerization in a solvent. 5. The method of claim 4,
The solvent may be selected from the group consisting of dimethylsulphoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylene carbonate, propylene carbonate propylene carbonate, aqueous sodium rhodanide solution and mixtures thereof. < Desc / Clms Page number 13 > 6. The method according to any one of claims 1 to 5,
Characterized in that a) contains from 8 to 12 mol% of comonomers. 7. The method according to any one of claims 1 to 6,
Wherein 1 to 5 mol% of a comonomer is present in b). 8. The method according to any one of claims 1 to 7,
And 1 to 5 mol% of a comonomer is present in the above c). 9. The method according to any one of claims 1 to 8,
Wherein the copolymer has a weight-average molar mass (Mw) of 15,000 to 80,000 g / mol. A method of producing a fiber or fiber precursor by melt spinning,
i. Wherein copolymerization of 95 to 80 mole% acrylonitrile and at least one comonomer is carried out in the presence of at least one initiator, and
ii. Wherein the copolymer is irradiated at the extruder outlet with an extruder having at least one nozzle suitable for spinning to form monofilaments or multifilaments,
The at least one comonomer
a) 5 to 20 mol% of at least one alkoxyalkyl acrylate of formula (I)

Wherein R = C _n H _{2n +1} and n = 1-8 and m = 1-8, especially n = 1-4 and m = 1-4,
b) from 0 to 10 mol% of at least one alkyl acrylate of formula II, and

Wherein R = C _n H _{2n + 1} and n = 1-18,
c) 0 to 10 mol% of at least one vinyl ester of formula (III);
Wherein R = C _n H _{2n + 1} and n = 1-18,
≪ / RTI > wherein the fiber or fiber precursor is melt spinnable. 11. The method of claim 10,
At least one softening agent is added immediately before or during the extrusion of step ii), wherein the softening agent is in particular water, nitroalkane, alkylalcohol, ionic liquids, glycols, dimethyl sulfoxide But are not limited to, dimethylsulphoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylene carbonate, propylene carbonate, sodium An aqueous sodium rhodanide solution, and mixtures thereof. ≪ Desc / Clms Page number 20 > The method according to claim 10 or 11,
Wherein the fibers are carbon fibers,
iii. Stabilizing the filament by temperature treatment at a temperature of 200 to 350 DEG C and
iv. Further comprising the step of carbonisation of the filament at a temperature of 800 to 1,200 占 폚. 13. The method of claim 12,
Characterized in that the step of stabilizing the filaments is carried out at a temperature of from 180 to 320 ° C, preferably from 180 to 300 ° C, particularly preferably from 180 to 250 ° C. 14. The method according to any one of claims 10 to 13,
The initiator may be selected from the group consisting of azo compounds, peroxide, hydroperoxides, alkylperoxides, peroxodicarbonates, peroxyesters, dialkylperoxides, ), Persulphates, perphosphates, redox initiators, and mixtures thereof. 11. A process for the preparation of fibers or fiber precursors by melt spinning, comprising the steps of: A fiber which is producible by spinning the copolymer according to any one of claims 1 to 10. 16. The method of claim 15,
Characterized in that the fibers are carbon fibers.

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